US3658481A - Flame ionization detector assembly - Google Patents

Flame ionization detector assembly Download PDF

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Publication number
US3658481A
US3658481A US25759A US3658481DA US3658481A US 3658481 A US3658481 A US 3658481A US 25759 A US25759 A US 25759A US 3658481D A US3658481D A US 3658481DA US 3658481 A US3658481 A US 3658481A
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US
United States
Prior art keywords
assembly
needle
passage
housing
valve seat
Prior art date
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Expired - Lifetime
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US25759A
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English (en)
Inventor
Claude Guillemin
Jean-Claude Badin
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Produits Chimiques Pechiney Saint Gobain
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Produits Chimiques Pechiney Saint Gobain
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/64—Electrical detectors
    • G01N30/68—Flame ionisation detectors

Definitions

  • a flame ionization detector assembly for use in gas chromatography including a detector and a gas sampling assembly comprising a housing defining primary passage means for gaseous effluent from a chromatography column, a needle and a valve seat, both of which are received in recesses defined by the housing and both of which define passages communicating with the primary passage means whereby a small portion of the gaseous effluent from the chromatography column passes from the primary passage means through the passages defined by the valve seat and the needle to a combustion zone.
  • This invention relates to flame ionization detectors, and more particularly-to flame ionization detectors suitable for use in separations by gas chromatography.
  • a detector assembly including a gas sampling assembly for use with a detector comprising a housing defining primary passage means for the gaseous effluent from the chromatography column, passage means for a fraction of the flow of column effluent, and a valve to control the flow of this fraction to the detector.
  • This assembly can be used in conjunction with a conventional detector including a burner head, measuring electrodes, temperature measuring means, an ignitor and a protective bell to provide a flame ionization detector having a minimum of dead volume which is capable of detecting sharp peaks without the occurrence of disturbances caused by too large a diversion in the primary gas flow.
  • the housing is in the form of a solid block, preferably formed of a metal, which defines the passage means therethrough as well as the recess for the glass flow control valve and the passages for the electrodes and other detector elements.
  • the housing block 1 is preferably formed of a metal, such as stainless steel, and defines a passage 2 through which the primary gas flow from the column can exit from the device.
  • the gaseous influent to the apparatus of the invention is fed to passage defined in flange 4 and annular element 3.
  • Passage 25 communicates with passage 2 so as to define a primary tube or passage through which the primary gas flow from the column may pass.
  • Housing block 1 also defines a recess adapted to receive a valve seat member 6 having a passage 7 having a small diameter therethrough communicating with the primary tube defined by passages 25 and 2 which is maintained in its recess by means of the abutting relationship of annular element 3.
  • the valve seat member 3 is preferably formed of a plastic material which is stable against chemical attack from the gaseous effluent of the column and thermally stable at the prevailing column effluent material.
  • a valve seat member formed of polytetrafluorethylene, although use can also be made of a variety of other materials.
  • Housing block 1 also defines a recess adapted to receive a coaxial needle 9 which extends through the recess, and is adapted to seat in valve seat element 6.
  • valve seat element 6 has a conical recess defined by surface 8 which is adapted to receive the corresponding conical end of needle 9 in a sealing relationship when the valve is closed.
  • the upper end of needle 9 is threadably engaged with housing block 1 by means of thread means 12, and needle 9 is adapted to be displaced into sealing engagement with valve seat 6 by means of a gear wheel 17 fixed to needle 9 by way of block 13 which is actuated by an endless screw 18 which extends through housing 1 where it is accessible on the outside thereof to rotate needle 9 about its cylindrical axis and thereby displace needle 9 relative to valve seat member 6.
  • needle 9 is sealed from its recess by means of toroidal sealing means 10 whereby the conical surface of needle 9 and the corresponding conical recess of surface 8 of seat element 6 define a space therebetween when the valve is at least partially open.
  • the space defined by needle 9 and surface 8 communicates on the one hand with passage 7 extending through seat member 6.
  • the space also communicates with passages 11 and 16 extending at least partially through needle 9 whereby gases are perknitted to flow through passage means 7 to the space defined by needle 9 and surface 8 and through passage means 11 and 16 to combustion chamber 26 defined by housing I.
  • passage 16 extends into combustion chamber 26
  • tube 16 is preferably formed'of a refractory material such as fused silica or the like extending through a bushing 15 formed of a plastic material, such as polytetrafiuoroethylene.
  • the lower postion of passage 11 is oblique relative to the axis of needle 9 and extends substantially perpendicular to the conical surface of needle 9 and to surface 8.
  • a variety of other positions of the lower portion of passage means 11 are similarly suitable in the invention to feed a small amount of the effluent to the combustion zone.
  • Housing 1 also defines a passage 19 for the introduction of a fuel gas, preferably hydrogen, to combustion chamber 26 by means of tube 20 extending through a plastic bushing 21. Similarly, housing 1 defines passage means 22 for the introduction of an oxygen-containing gas such as air to combustion zone 26. While it is not illustrated in the drawing, the top of combustion zone 26 may be provided with a protective bell of the type conventionally used in flame ionization detectors, which may be threadably engaged with threads 23 and sealed by sealing means 24. Also not illustrated in the drawing for the sake of simplicity are the standard elements of a flame ionization detector including the measuring electrodes, temperature measuring means, such as a thermocouple, and an electrical resistance ignitor.
  • the gaseous effluent from a chromatography column is fed to the primary tube defined by passages 25 and 2 whereby the gases flow therethrough.
  • the needle valve is opened by causing shaft 18 to rotate, thereby turning wheel 17 and displacing needle 9 upwardly away from valve seat member 6 to define a space between needle 9 and surface 8 of valve seat member 6. This enables a small portion of the gas passing through passage 25 to pass through passage 7 in valve seat member 6 and through passage 11 in needle 9 and through tube 16 where the gas is contacted with a hydrogenoxygen flame in combustion zone 26. Ionization of the gas in the flame can then be measured by means of the electrodes in a conventional manner.
  • the device of the present invention has a very small dead volume since it makes use of passage means having a small diameter and short length joining the primary gas flow and the flame.
  • the quantity of gas samples can easily be regulated by displacement of needle 9 relative to valve seat member 6.
  • the various elements are not restricted to the configurations illustrated in the drawing.
  • the tube for primary gas flow may be rectilinear or have a regular curvature instead of the right angle tube illustrated.
  • a flame ionization detector assembly for use in gas chromatography in which a small portion of the effluent from a chromatography column is passed to a combustion zone for flame ionization
  • the improvement comprising a housing, said housing defining first passage means for gaseous effluent from a chromatography column, a needle and valve seat means, both of which are adapted to be received in recesses defined by said housing with the needle being mo'veable relative to the valve seat means to define a space therebetween when the needle is moved away from the valve seat means to an open position
  • said valve seat means including a small passage communicating with the first passage and said needle including an internal passage communicating with the combustion zone and the space defined between the needle and the valve seat means, whereby a small portion of gas passes from the first passage through the small passage of the valve seat means and the internal passage of the needle to the combustion zone, and passage means to supply an oxygen-containing gas and a fuel gas to the combustion zone.
  • valve seat means has a conical recess formed therein and said needle has a conical section on one end thereof, said conical recess being adapted to receive said conical section of said needle in sealing relation when said needle is in closed position.
  • valve seat means is formed of a plastic.
  • An assembly as defined in claim 7 which includes a gear wheel fixed to said needle and an endless screw engaged with said gear wheel, said needle being rotatable in response to rotation of said screw.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
US25759A 1969-04-11 1970-04-06 Flame ionization detector assembly Expired - Lifetime US3658481A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR6911175A FR2040735A5 (enrdf_load_stackoverflow) 1969-04-11 1969-04-11

Publications (1)

Publication Number Publication Date
US3658481A true US3658481A (en) 1972-04-25

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ID=9032214

Family Applications (1)

Application Number Title Priority Date Filing Date
US25759A Expired - Lifetime US3658481A (en) 1969-04-11 1970-04-06 Flame ionization detector assembly

Country Status (6)

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US (1) US3658481A (enrdf_load_stackoverflow)
BE (1) BE748794A (enrdf_load_stackoverflow)
DE (1) DE2017301A1 (enrdf_load_stackoverflow)
FR (1) FR2040735A5 (enrdf_load_stackoverflow)
GB (1) GB1297062A (enrdf_load_stackoverflow)
NL (1) NL7004779A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4684509A (en) * 1984-07-17 1987-08-04 Tibor Bernath Apparatus for measuring gas concentrations in a hot gas sample withdrawn from a process chamber

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3215499A (en) * 1960-11-18 1965-11-02 Ici Australia Ltd Apparatus for detecting the presence of organic gases and vapours
US3230046A (en) * 1962-10-29 1966-01-18 Beroza Morton Apparatus and method for ultramicro determination of the carbon skeleton and other structural features of organic compounds
US3399974A (en) * 1965-03-02 1968-09-03 Hewlett Packard Co Gas analyzer
US3502439A (en) * 1966-12-19 1970-03-24 Shell Oil Co Portable gas-leak detector

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3215499A (en) * 1960-11-18 1965-11-02 Ici Australia Ltd Apparatus for detecting the presence of organic gases and vapours
US3230046A (en) * 1962-10-29 1966-01-18 Beroza Morton Apparatus and method for ultramicro determination of the carbon skeleton and other structural features of organic compounds
US3399974A (en) * 1965-03-02 1968-09-03 Hewlett Packard Co Gas analyzer
US3502439A (en) * 1966-12-19 1970-03-24 Shell Oil Co Portable gas-leak detector

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4684509A (en) * 1984-07-17 1987-08-04 Tibor Bernath Apparatus for measuring gas concentrations in a hot gas sample withdrawn from a process chamber

Also Published As

Publication number Publication date
FR2040735A5 (enrdf_load_stackoverflow) 1971-01-22
BE748794A (fr) 1970-10-12
NL7004779A (enrdf_load_stackoverflow) 1970-10-13
DE2017301A1 (de) 1970-10-22
GB1297062A (enrdf_load_stackoverflow) 1972-11-22

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